Methods for removing a fastener from a wafer carrier

Abstract

The present disclosure relates to systems and methods for affixing and/or removing a fastener from a wafer-carrying pod. The system includes a robotic arm with a screw tool assembly disposed at the far end of the robotic arm. The screw tool assembly includes a lower sleeve configured to receive a fastener. A screwdriver is disposed within an upper sleeve of the screw tool assembly, and a motor is provided to rotate the screwdriver. In use, the screw tool assembly is positioned over the fastener so the lower sleeve surrounds the fastener and the screwdriver engages the fastener. The screwdriver unscrews the fastener from the pod, and the fastener head is received within the lower sleeve.

What is claimed is: 
     
       1. A method of removing a fastener from a wafer carrier, the method comprising:
 moving a robotic arm to position a screw tool assembly over the fastener, 
 
       such that a lower sleeve element of the screw tool assembly surrounds a head of the fastener, the lower sleeve element including an internal thread having at least one turn;
 pushing the screw tool assembly downwards such that the lower sleeve element is pushed into an upper sleeve element of the screw tool assembly and a screw drive of the fastener is engaged by a screwdriver head within the upper sleeve element; and 
 unscrewing the fastener by rotating the screwdriver head with a motor, 
 
       such that the head of the fastener is captured by the internal thread of the lower sleeve element and separated from the wafer carrier. 
     
     
       2. The method of  claim 1 , wherein a thread pitch of the internal thread of the lower sleeve element is greater than a height of the head of the fastener. 
     
     
       3. The method of  claim 2 , wherein a ratio of the thread pitch to the fastener head height is about 1.2 or greater. 
     
     
       4. The method of  claim 1 , wherein a lower thread angle and an upper thread angle of the internal thread are equal to each other. 
     
     
       5. The method of  claim 4 , wherein the lower thread angle and the upper thread angle are from greater than 90° to about 170°. 
     
     
       6. The method of  claim 1 , further comprising moving the robotic arm to a screw buffer table and rotating the screwdriver head to release the fastener into an aperture in the screw buffer table. 
     
     
       7. The method of  claim 6 , wherein the screw buffer table comprises a plurality of apertures for holding a plurality of fasteners. 
     
     
       8. The method of  claim 1 , wherein a width of the lower sleeve element is greater than a diameter of the head of the fastener. 
     
     
       9. The method of  claim 1 , wherein the internal thread has a minimum thread depth of about 0.5 mm. 
     
     
       10. The method of  claim 1 , further comprising moving the screw tool assembly upwards as the fastener is unscrewed. 
     
     
       11. The method of  claim 1 , wherein the entire fastener is retained within the lower sleeve element. 
     
     
       12. The method of  claim 1 , wherein the movement of the robotic arm and the screw tool assembly is controlled automatically or manually. 
     
     
       13. The method of  claim 1 , wherein a camera attached to the screw tool assembly is used to position the screw tool assembly over the fastener. 
     
     
       14. The method of  claim 1 , wherein a door held in place by the fastener is removed from the wafer carrier, and the wafer carrier is subsequently sent to a cleaning system. 
     
     
       15. A method of removing a fastener from a wafer carrier, the method comprising:
 locating the wafer carrier in a known position relative to a robotic arm; 
 moving the robotic arm to position a screw tool assembly over the 
 
       fastener, such that a lower sleeve element of the screw tool assembly surrounds a head of the fastener, the lower sleeve element including an internal thread having at least one turn;
 pushing the screw tool assembly downwards such that the lower sleeve element is pushed into an upper sleeve element of the screw tool assembly and a screw drive of the fastener is engaged by a screwdriver head within the upper sleeve element; and 
 unscrewing the fastener by rotating the screwdriver head with a motor, 
 
       such that the head of the fastener is captured by the internal thread of the lower sleeve element and separated from the wafer carrier. 
     
     
       16. The method of  claim 15 , further comprising moving the screw tool assembly upwards as the fastener is unscrewed. 
     
     
       17. The method of  claim 15 , further comprising moving the robotic arm to a screw buffer table and rotating the screwdriver head to release the fastener into an aperture in the screw buffer table. 
     
     
       18. A method for removing a fastener from a wafer carrier, the method comprising:
 placing the wafer carrier on an entry load port of a system that also comprises a robotic arm having a screw tool assembly disposed at an operating end thereof, wherein the screw tool assembly comprises:
 an upper sleeve element having a screwdriver head disposed therein and a lower aperture; 
 a motor configured to rotate the screwdriver head; and 
 a lower sleeve element including an internal thread having at least one turn, the lower sleeve being sized to fit within the upper sleeve and to move telescopically within the lower aperture of the upper sleeve element; 
 
 moving the robotic arm to position the screw tool assembly over the fastener, such that the lower sleeve element of the screw tool assembly surrounds a head of the fastener; 
 pushing the screw tool assembly downwards such that the lower sleeve element is pushed into the upper sleeve element and a screw drive of the fastener is engaged by the screwdriver head within the upper sleeve element; and 
 unscrewing the fastener by rotating the screwdriver head with the motor, and capturing the head of the fastener with the internal thread of the lower sleeve element to remove the fastener from the wafer carrier. 
 
     
     
       19. The method of  claim 18 , further comprising moving the screw tool assembly upwards as the fastener is unscrewed. 
     
     
       20. The method of  claim 18 , further comprising moving the robotic arm to a screw buffer table and rotating the screwdriver head to release the fastener into an aperture in the screw buffer table.